(a) Field of the Invention
The present invention relates to a liquid crystal display, and particularly to a vertically aligned liquid crystal display having a pixel area divided into a plurality of small domains for wide viewing angle.
(b) Description of Related Art
In general, a liquid crystal display (referred to as an xe2x80x9cLCDxe2x80x9d hereinafter) has an upper panel, a lower panel and a liquid crystal layer disposed therebetween. The upper panel has a common electrode, a plurality of color filters and the like, and the lower panel has a plurality of thin film transistors, a plurality of pixel electrodes connected thereto and so on. In addition, a pair of polarizers are attached to the panels. The pixel electrodes and the common electrode are applied with electrical voltages to generate electric field which varies the orientation of liquid crystal molecules. The variation of the orientation of the liquid crystal molecules changes the polarization of light incident on the liquid crystal layer after passing through one of the polarizers, thereby controlling the transmittance of the light out of the other polarizer.
One drawback of a conventional LCD is its narrow viewing angle. Several methods for widening the viewing angle have been developed. One of the methods is to align the long axes of the liquid crystal molecules vertical to the panels and to form apertures or protrusions in the pixel electrodes and/or in the common electrode facing the pixel electrodes. The domain defining members such as aperture or protrusions define domains, and the domains in turn define the alignment of the liquid crystal molecules therein.
The apertures formed in the pixel electrodes and the common electrode result in a fringe field. By using the fringe field, the tilt directions of the liquid crystal molecules are controlled to enlarge the viewing angle.
The protrusions are provided on the pixel electrodes and the common electrode formed in the upper and the lower panels. The electric field altered by the protrusions are used to control the tilt directions of the liquid crystal molecules.
Another method is by forming apertures in the pixel electrodes of the lower panel, while having protrusions on the common electrode of the upper panel. The tilt directions of the liquid crystal molecules are controlled to form domains by using the fringe field generated by the apertures and the protrusions.
In addition, gate lines and data lines provided in the lower panel and arranged in rows and columns carry scanning signals and image signals, and the pixel electrodes and the thin film transistors are disposed in rectangular areas defined by the intersections of the gate lines and the data lines. When the scanning signals and the image signals are transmitted by the gate lines and the data lines the signals influence the electric fields adjacent thereto, and the stability of the domains and the image quality deteriorate.
It is therefore an object of the present invention to provide a liquid crystal display having improved image quality by preventing electric field of a gate line and a data line from influencing on the electric field in a domain.
According to the present invention, these and other objects are accomplished by disposing a storage electrode wire between a gate line or a data line and a pixel electrode.
According to one aspect of the present invention, first, second and third signal lines are formed on a first substrate. The second signal line is insulated from and intersects the first signal line, and the third signal line is insulated from the first and the second signal lines. A pixel electrode is formed in a pixel area, which is defined by intersections of the first and the second signal lines. The pixel electrode has a plurality of partitions and a plurality of connections connecting the partitions. A switch is connected to the first signal line, the second signal line and the pixel electrode.
In addition, a common electrode and a plurality of domain defining members are formed on a second substrate. According to the present invention, a first of the partitions of the pixel electrode has a first side and a second side shorter than the first side, which are substantially parallel to the first and the second signal lines, respectively. The third signal line has a first portion located between the first side of the first partition and the first signal line adjacent to the first side of the first partition.
A second of the partitions of the pixel electrode may have a first side and a second side shorter than the first side, which are substantially parallel to the second and the first signal lines, respectively. In this case, it is preferable that the third signal line has a second portion disposed between the first sides of the second partition and the second signal line.
The second portion of the third signal line preferably overlaps in part the first sides of the partitions of the pixel electrode.
The third signal line may further have a third portion adjacent to the second sides of the partitions of the pixel electrode, and it is preferable that the second portion of the third signal line is substantially covered by the pixel electrode. In addition, the third signal line may have a fourth portion spaced apart by at least 3 xcexcm from the second sides of the pixel electrode. The third signal line is preferably formed of the same layer as the first signal line.
Alternatively, the third signal line may further have a portion located between the partitions of the pixel electrode.
A third of the partitions of the pixel electrode may have a first side and a second side shorter than the first side, which are substantially parallel to the second and the first signal lines, respectively. In this case, the first to the third partitions are preferably arranged along the first signal lines.
Preferably, the third signal line is applied with a common voltage which is applied to the common electrode.
According to another aspect of the present invention, an LCD includes first and second panels opposite each other and a liquid crystal layer therebetween. The first panel has a first electrode, a first domain defining member and a signal wire, and the second panel has a second electrode and a second domain defining member. According to the present invention, the first and the second domain defining members define a domain where molecules of the liquid crystal layer are aligned substantially in one direction. The planar shape of the domain has a first side and a second side of being shorter than the first side. The first panel also has an interference protection wire which is located between the first side of the domain and the signal wire adjacent thereto.
Preferably, the first or second domain defining members include a plurality of partitions with a first partition disposed in one of two halves of a pixel area for further dividing into two domains the one half pixel area and a second and third partition for dividing the second half of the pixel areas into three domains. The first partition is preferably disposed in a direction transverse to the direction of the second and third partitions.
According to still another embodiment of the invention, a liquid crystal display (LCD) comprising: a gate wire and a storage electrode wire formed on a substrate and covered with a gate insulating layer; a data wire formed on the gate insulating layer and covered with a passivation layer; a pixel electrode formed on the passivation layer, the pixel electrode is divided into a plurality of partitions, wherein the storage electrode wire is disposed between the partitions and the gate or the data wires. Preferably, the storage electrode wire is spaced apart from a first partition by at least 3 xcexcm.